JP2007320691A - Vibration-type conveying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration-type conveying device capable of reducing the size and the cost of a driving circuit thereof, applying a consistent driving voltage to a vibration generation source, and easily setting a driving state. <P>SOLUTION: The vibration-type conveying device has a piezoelectric driving body 160 having an elastic metal plate connected to a conveying body as a vibration generation source, and a lamination type piezoelectric element which is adhered to the elastic metal plate via an insulating layer with a plurality of piezoelectric layers and a plurality of electrode layers being alternately laminated thereon; and comprises a DC power supply 120 for outputting the DC voltage, an inverter 130 for inverting the AC voltage into the AC output voltage by the PWM drive and applying the inverted voltage to the piezoelectric element, an inductor 140 to be connected between the inverter and the piezoelectric element, a voltage detection means 170 for directly detecting the both-terminal voltage of the piezoelectric element, and an inverter control means 180 capable of setting the frequency and the voltage of the inverter and controlling the inverter according to the detected voltage of the voltage detection means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vibration type conveying apparatus, and more particularly to a configuration of an excitation driving circuit suitable for driving a vibration generating source including a piezoelectric element.

  In general, a vibration type conveying apparatus that vibrates a conveying body by applying an AC voltage to a vibration generating source and conveys an object to be conveyed is frequently used in various production lines. In particular, as a component supply device that supplies a large number of fine components such as surface-mount electronic components and crystal oscillators for oscillators, the vibratory transfer device greatly contributes to speeding up the production line.

  Conventional vibration transfer devices use an electromagnetic vibration source or a piezoelectric vibration source as the vibration generation source. However, with the recent reduction in size and speed of vibration transfer devices, there are many piezoelectric vibration sources. It has come to be used. As this piezoelectric vibration source, a piezoelectric driving body in which a piezoelectric element is bonded to an elastic metal plate (metal shim plate) is often used. In this case, since the elastic metal plate is electrically connected to the frame of the device, an insulating transformer is connected to the output stage of the drive circuit for excitation (after the inverter described later) in order to ensure electrical safety. However, the piezoelectric element is driven through this insulating transformer (for example, the column “Problems” in Patent Documents 1 and 2 below).

  On the other hand, an insulation type piezoelectric vibration source in which a piezoelectric element is bonded to the elastic metal plate via an insulating layer is known, and the vibration performance of the piezoelectric element can be improved by the structure via the insulating layer. In addition, it is possible to omit an insulating cover and the like, and further, it is possible to reduce the size and cost of the excitation drive circuit by omitting the insulating transformer (for example, Patent Document 1 below). And 2).

  Further, as the configuration of the excitation drive circuit used for driving the vibration source in the vibration type conveying apparatus as described above, the AC voltage of the commercial power source is converted into a DC voltage by a rectifier and a DC / DC converter, The AC voltage generated by supplying this DC voltage to the inverter is applied to the vibration source, the current supplied to the vibration source is detected, and the phase difference between the current and the output voltage of the inverter is obtained to detect vibration. There is known a technique in which the applied power of the generation source is calculated and the resonance frequency of the vibration generation source is detected using the applied power (see, for example, Patent Documents 3 and 4 below).

JP 11-31855 A JP 2003-134893 A JP-A-3-223014 Japanese Patent Laid-Open No. 4-144819

  By the way, in Patent Documents 1 and 2 described above, it is described that an insulating transformer is not required by using a piezoelectric element having an insulating structure. However, if the insulating transformer is simply removed from a conventional driving circuit for excitation, the inverter circuit There is a problem that the operation of the piezoelectric element becomes unstable due to the high frequency noise and the noise increases. In addition, since the conventional drive circuit for excitation requires a high voltage exceeding 200 V in order to ensure the driving force and amplitude of the piezoelectric element required for the vibratory transfer device, this increases the DC voltage supplied to the inverter. A booster circuit is required to convert the voltage. However, if this step-up circuit is inserted, it is inevitable to increase the size and cost of the circuit in order to sufficiently secure the rated current. Therefore, even if the above-described insulation transformer can be omitted as described above, in practice, There is a problem that it is difficult to reduce the size and the price.

  Moreover, in the method of calculating | requiring the resonance point of the said patent documents 3 and 4, when the applied electric power is calculated | required by the product of the output voltage of an inverter, an electric current, and a power factor, the phase difference of an output voltage and an electric current is calculated | required correctly. Since this is difficult, there is a problem that the resonance point cannot be obtained accurately. Specifically, the method described in the above publication uses the zero-cross detector and the microcomputer interrupt operation because noise is superimposed on the detected current, but this also increases the error. Since an accurate phase difference cannot be calculated, it is extremely difficult to construct a practical device. For example, in the above-mentioned patent document, the voltage between both ends of a current detection resistor incorporated in the circuit for detecting the current value is input to the control circuit through the filter, but this cannot sufficiently reduce the detection error. . In particular, when a piezoelectric element is used as a vibration source, the current is extremely weak (usually about several mA), and when a low resistance for current detection (usually 1Ω or less) is used, the detection voltage Therefore, it is impractical to obtain the applied power from the supply voltage, current, and phase difference.

  Furthermore, the vibration generation source may be configured in various sizes depending on the conveyance body or the conveyance object, or the number of vibration generation sources to be used may be increased or decreased. For example, two piezoelectric elements may be used in a small apparatus, but four piezoelectric elements of the same size may be used in a large apparatus. Even in these cases, if the drive current is within the rating, a controller having the same specification is often used. At this time, the same inverter drive voltage may be applied when the element is small or the number is small, that is, when the drive current is small, and when the element is large or the number is large, that is, when the drive current is large. The voltage applied to the actual element varies depending on the voltage drop due to the reactance in the middle or the internal resistance of the switching element (FET). Specifically, when there are many elements, the voltage drops and the vibration source cannot be driven sufficiently. If the voltage is set assuming that there are many elements, on the contrary, if the number of elements is small, an excessive voltage may be applied to destroy the elements.

  On the other hand, as another method for detecting the resonance frequency, there is known a method for detecting vibration acceleration with an acceleration sensor attached to a vibration source or a carrier while sweeping the drive frequency. There is a problem that the cost is high because it is necessary to attach to the device, and in the detection method using the phase difference between the detection signal of the acceleration sensor and the output voltage, the phase changes by 180 degrees depending on the mounting direction of the sensor, There is also a problem that phase delay occurs.

  Therefore, the present invention solves the above-mentioned problems, and the problem is that it is possible to reduce the size and cost of the excitation drive circuit and to apply a stable drive voltage to the vibration source. It is also possible to provide a novel vibratory transfer device that can easily set the drive frequency and the drive voltage.

  In view of such a situation, the vibration transfer device of the present invention is a vibration transfer device that vibrates a transfer body by transferring an AC voltage to a vibration generation source to transfer a transfer object. An elastic metal plate that is directly or indirectly connected to the carrier, and an adhesive layer that is bonded to the elastic metal plate via an insulating layer, and a plurality of piezoelectric layers and a plurality of electrode layers are alternately laminated. Using a piezoelectric driving body having a laminated piezoelectric element, a DC power source that outputs a required DC voltage, an inverter that converts the AC voltage into an AC output voltage by PWM driving, and applies the AC voltage to the piezoelectric element, and An inductor connected between an inverter and the piezoelectric element, voltage detection means for directly detecting a voltage across the piezoelectric element, a frequency and a voltage value of the inverter can be set, and the voltage detection Characterized by comprising the inverter control means which is capable of controlling the inverter in accordance with the voltage detection value of the stage, the.

  According to the present invention, since the elastic metal plate and the piezoelectric element are bonded via the insulating layer as the vibration generation source, it is not necessary to provide an insulating transformer in the driving circuit for excitation, and the laminated piezoelectric element is By using it, a booster circuit becomes unnecessary, so that the drive circuit for excitation can be reduced in size and price. In addition, by connecting an inductor between the inverter and the piezoelectric element, it is possible to remove high-frequency noise from the inverter even if the insulation transformer is omitted. Therefore, the operation stability of the piezoelectric element is improved and noise is reduced. It becomes possible to plan. In addition, by providing voltage detection means that directly detects the voltage across the piezoelectric element, it is possible to obtain the actual voltage detection value applied to the piezoelectric element, so driving due to changes in the capacity, number, etc. of the piezoelectric element Even if the voltage drop based on the internal resistance of the inverter switching element or the equivalent resistance of the inductor changes due to current fluctuation, the drive conditions (drive frequency and drive voltage) of the piezoelectric element are set without being affected by the change. It becomes possible.

  In addition, as a control mode of the inverter by the inverter control means, the drive frequency of the inverter may be controlled, the drive voltage value of the inverter may be controlled, or both are controlled. It may be. Further, it may be one that performs constant control during operation, or one that is not normally controlled but that is controlled only when necessary.

  In the present invention, it is preferable that the inverter control unit controls the inverter so as to keep a voltage detection value of the voltage detection unit constant. By controlling so that the voltage detection value is kept constant by the inverter control means, it is possible to reliably set the voltage value actually applied to the piezoelectric element. Specifically, even if the size and number of vibration generation sources (that is, the drive current) fluctuate, fluctuations in the actual voltage applied to the vibration generation sources are suppressed, so that a stable excitation operation can be realized. . In particular, in order to remove the high frequency noise from the PWM drive waveform of the inverter and apply it to the vibration source, the above inductor is required, but the internal resistance of this inductor and the inverter output voltage are actually applied to the vibration source. The difference between the two voltages differs depending on the magnitude of the drive current, so the conventional method cannot grasp the exact voltage applied to the vibration source, and the vibration source Many demerits are caused at the time of the operation adjustment or the operation stability. However, in the present invention, the voltage at both ends of the vibration source is directly detected and the voltage detection value is fed back to control the inverter, so that the above disadvantages can be completely avoided.

  In the present invention, it is preferable that the voltage detection means includes a detection transformer in which a voltage at both ends of the vibration generating source is given to the primary side and a secondary side is connected to the inverter control means. According to this, by detecting the voltage at both ends of the vibration generation source via the detection transformer, it is possible to reliably detect the voltage at both ends, and at the same time, if only voltage detection is required, an ultra-small and high impedance transformer is sufficient. Without hindering downsizing of the drive device, power loss and cost increase can be suppressed. Moreover, even when charge charges are generated in the vibration generating source, the charge is discharged on the primary side of the detection transformer, so that no charge charge discharge resistance (high resistance connected to both ends of the element) is required. Further, when the vibration source is short-circuited, the secondary voltage of the detection transformer becomes zero, so that the short-circuit of the vibration source can be reliably detected. Therefore, a resistor for detecting overcurrent is not necessary, and wasteful power consumption can be prevented. As the voltage detection means, in addition to the above detection transformer, for example, a voltage detection circuit using an operational amplifier can be used.

  In the present invention, the inverter control means includes a resonance point detection means for obtaining a resonance frequency by changing a frequency of the output voltage while detecting a minimum point of the voltage detection value while maintaining a voltage command value constant. It is preferable. The means can be realized, for example, by making the voltage command value of the inverter constant and obtaining the minimum point of the voltage detection value of the voltage detection means while sweeping the frequency of the output voltage. This is because the impedance of the piezoelectric element shows a minimum value at the resonance frequency. Further, it can be realized by obtaining the maximum point of the voltage command value of the inverter control means while sweeping the frequency of the output voltage while controlling the output voltage by the inverter control means so as to keep the voltage detection value constant. .

  The inverter control means corrects a voltage control parameter according to a fluctuation ratio of a voltage drop amount of the voltage detection value or a voltage increase amount of a voltage command value at a resonance point, thereby suppressing an acceleration fluctuation of the piezoelectric element. Preferably, the control means is included. For example, during driving after the inverter driving frequency is set to the resonance frequency in advance, at least one of the voltage detection value or voltage command value, the resonance frequency, and the voltage drop amount at the resonance point varies more than a predetermined threshold. If it occurs, the drive frequency is reset to the newly detected resonance frequency, and the voltage control parameters (voltage command value, voltage target value, etc.) are corrected according to the fluctuation ratio of the voltage drop amount. Thus, variation in acceleration of the piezoelectric element can be suppressed. This is because when the vibration load changes, the voltage drop amount or the voltage increase amount of the voltage command value near the resonance point of the resonance frequency and voltage detection value and the acceleration change in proportion to the change amount of the vibration load. Therefore, acceleration can be achieved by using the fluctuation ratio of the voltage drop at the resonance point (without feedback control of the voltage detection value) or the voltage increase of the voltage command value (with feedback control of the voltage detection value) as a correction parameter. Fluctuations can be suppressed.

  On the other hand, as another vibration type conveying apparatus of the present invention, in the vibration type conveying apparatus that conveys the conveyed object by vibrating the conveying body by applying an AC voltage to the vibration generating source, the vibration generating source is used for excitation. A DC power source that includes a piezoelectric element and outputs a required DC voltage; an inverter that converts the DC voltage into an AC output voltage by PWM drive; and that is applied to the piezoelectric element; and between the inverter and the piezoelectric element A voltage detecting means including a connected inductor, a detection transformer for directly detecting a voltage across the piezoelectric element, a frequency and a voltage value of the inverter can be set, and according to a voltage detection value of the voltage detecting means And inverter control means configured to control the inverter.

  In this case, it is preferable that the inverter control means controls the inverter so as to keep the detected voltage value constant. The inverter control means may include a resonance point detection means for obtaining a resonance frequency by changing a frequency of the output voltage while detecting a minimum point of the voltage detection value while maintaining a voltage command value constant. preferable. Alternatively, the inverter control means includes resonance point detection means for obtaining a resonance frequency by changing a frequency of the output voltage while detecting the maximum value of the voltage command value while controlling the voltage detection value to be constant. preferable. Further, the inverter control means, when the voltage detection value fluctuates more than a predetermined threshold during driving after setting the drive frequency of the inverter to the resonance frequency in advance, the resonance frequency is calculated from the voltage detection value. And the drive frequency is reset to the newly detected resonance frequency, and the voltage setting value or the voltage target value is corrected according to the fluctuation ratio of the voltage drop amount of the voltage detection value near the resonance point. It is preferable to include acceleration control means for suppressing fluctuations in acceleration of the piezoelectric element.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a schematic configuration of an excitation drive circuit 100 used in a vibration type conveying apparatus according to the present invention. The excitation drive circuit 100 rectifies and smoothes the AC voltage supplied from the commercial power source 1 and steps down the voltage as necessary to supply a required DC voltage (hereinafter simply referred to as “supply voltage”) Vo. 120 and an inverter 130 for converting the supply voltage Vo supplied from the DC power source 120 into an AC output voltage Vp having a predetermined frequency. The output voltage Vp supplied from the inverter 130 is applied to the piezoelectric element 34 which is an excitation element of the vibration generation source via the inductors 140 and 150. These inductors 140 and 150 are ripple removing choke coils. Only one of the inductors 140 and 150 may be provided, but it is preferable to provide both of the inductors 140 and 150 on both sides of the piezoelectric element 34, which is preferable in terms of noise countermeasures.

  Further, the excitation drive circuit 100 includes a detection transformer 170 which is a voltage detection means for detecting the voltage Vs across the piezoelectric element 34, and the output of the detection transformer 170 is connected to the control unit 180. The control unit 180 is configured by, for example, a microprocessor unit (MPU) or the like, and a voltage detection value Vd indicating a voltage Vs across the piezoelectric element 34 detected via the detection transformer 170 (if the value has a predetermined correlation with Vs). The control signal S may be output in accordance with Vs. The control signal S substantially includes a frequency command value that determines the frequency of the inverter 130 and a voltage command value that determines the voltage value, and is input to the PWM circuit 190 that is an inverter drive circuit. D is output to drive the switching elements 131, 132, 133, and 134 including FETs of the inverter 130, and the inverter 130 generates the predetermined AC output voltage Vp by PWM driving.

  The output voltage Vp of the inverter 130 is set by the width (duty ratio) and the period T of the rectangular pulse P corresponding to the drive signal D of the PWM circuit 190. For example, the effective voltage value changes as the duty ratio of the rectangular pulse P changes according to the drive signal D. Further, the drive frequency (f = 1 / T) is changed by changing the period t of the rectangular pulse P or the alternating period T of the positive and negative rectangular pulses P in accordance with the drive signal D. The duty ratio and frequency are controlled by the control signal S output from the control unit 180. The waveform of the output voltage Vp shown in the frame of the two-dot chain line in FIG. 1 is a schematic diagram showing only the principle, and does not accurately show the relationship between the switching cycle t of the inverter and the cycle T of the output voltage Vp. Absent.

  The control unit 180 of the present embodiment includes a setter 181 that can set the voltage reference value Vr and a setter 182 that can set the frequency reference value fr. The control unit 180 and the PWM circuit 190, which are inverter control means, control the inverter 130 so that the voltage value and the frequency correspond to the voltage reference value Vr and the frequency reference value fr. In addition, the voltage Vs across the piezoelectric element 34 is detected via the detection transformer 170, and the control unit 180 can control the voltage Vs across the piezoelectric element 34 to be constant according to the voltage detection value Vd. ing. For example, the voltage Vs across the piezoelectric element 34 is directly detected, and the inverter 130 is controlled so that the voltage detection value Vd corresponding to the voltage Vs is held constant (for example, the voltage reference value Vr). Compared to when the inverter is operated only by setting the voltage command value to the inverter, it is always unaffected by fluctuations in the size and number of vibration sources (fluctuation in drive current) or fluctuations in vibration load. A stable driving voltage can be provided. In addition, since an accurate drive voltage can be applied to the vibration generation source, the vibration generation efficiency can be increased by optimizing the drive voltage.

  In the present embodiment, the resonance frequency of the piezoelectric element 34 can be easily detected only by the above configuration. For example, the control unit 180 monitors the voltage detection value Vd while generating the control signal S so as to gradually change (sweep) the drive frequency while keeping the output voltage Vp supplied by the inverter 130 constant. The minimum point of the voltage detection value Vd (the impedance minimum point of the vibration generating source) can be detected as the resonance frequency. Further, when the drive frequency is gradually changed while performing the feedback control for keeping the voltage detection value Vd detected through the detection transformer 170 constant as described above, the voltage command value ( For example, the maximum point of the difference Vr−Vd) between the voltage reference value Vr and the voltage detection value Vd can be detected as the resonance frequency.

  The resonance frequency can be detected manually. For example, the resonance frequency can be automatically detected by a resonance point detection program that can be executed by the control unit 180. In other words, the drive frequency is changed (sweep) at a constant step amount by a control signal S, and the voltage detection value Vd (without voltage control) or the voltage command value (with voltage control) is monitored. Then, the frequency sweep may be continued until the minimum point of the voltage detection value Vd or the maximum point of the voltage command value is reached. In this case, in order to detect the resonance point more accurately, the frequency change direction is reversed and the step amount is reduced when the minimum point of the voltage detection value Vd or the maximum point of the voltage command value is exceeded during frequency sweep. It is also possible to take a method of continuing detection. The resonance point detecting means is realized by the control unit 180 set to operate as described above (for example, an operation of executing a resonance point detection program prepared in the control unit 180).

  FIG. 2 is a schematic side view of the vibration type conveying apparatus 10 including the vibration generating source 3 including a piezoelectric element as the piezoelectric element 34, FIG. 2A is a schematic front view of the present embodiment, and FIG. It is a schematic plan view which abbreviate | omits and shows the conveyance body of this embodiment.

  The vibration type conveying apparatus 10 of the present embodiment includes a base 1, a carrier 2 disposed above the base 1, a vibration source 3 for vibrating the carrier 2, and a vibration source 3. On the other side part (upper end) of the coupling member 4 connected to one side part (lower end), the first elastic support body 5 connected between the carrier 2 and the coupling member 4, and the vibration generating source 3 An inertial body 6 connected as a free end and a second elastic support 7 coupled between the coupling member 4 and the base 1 are provided. The base 1 includes a support plate 1A disposed on the installation surface, and a mounting plate 1B fixed on the support plate 1A and the second elastic support 7 fixed through bolts or the like. Yes.

  The transport body 2 has an attachment material 2A fixed to the first elastic support body 5 via bolts and the like, and a transport material 2B fixed on the attachment material 2A. Groove-shaped tracks are formed. The track extends in the left-right direction in FIG. 2 and holds a component (not shown) while the component is moved in a direction indicated by an arrow F (hereinafter simply referred to as “conveying direction F”) by vibration S3 transmitted from a vibration generating source 3 to be described later. )).

  The vibration generating source 3 is constituted by a piezoelectric vibration source. Specifically, this piezoelectric vibration source has a bimorph structure in which a piezoelectric layer is formed on both the front and back surfaces of an elastic plate and bent by applying a predetermined voltage to these piezoelectric layers. Have. Of course, it may be a unimorph type structure in which a piezoelectric layer is formed only on one side of the elastic plate. These piezoelectric vibration sources bend and vibrate at a frequency corresponding to the frequency by supplying AC power having a predetermined frequency from the outside.

  A specific example of the vibration source 3 is shown in FIG. As shown in FIG. 8, an insulating layer 32 composed of a synthetic resin layer, a resin film substrate, a glass epoxy substrate or the like is fixed to the surface of an elastic metal plate 31 such as a metal shim plate by adhesion or the like. A conductive layer 33 is formed thereon. A piezoelectric element 34 is laminated on the conductive layer 33. The insulating layer 32 and the conductive layer 33 are preferably composed of an insulating substrate and a wiring pattern deposited thereon. For example, the insulating layer 32 and the conductive layer 33 are composed of a flexible wiring substrate made of polyimide resin or the like, glass epoxy, or the like. It can be constituted by a hard wiring substrate, a ceramic substrate or the like. The piezoelectric element 34 is bonded and fixed on the conductive layer 33 with a conductive adhesive such as solder or conductive paste.

  As shown in FIG. 9, the piezoelectric element 34 has a laminated structure in which a plurality of piezoelectric layers 341 and a plurality of internal electrodes 342 and 343 or external electrodes 344 and 345 are alternately laminated. The external electrode 344 is conductively connected to the internal electrode 342 at the side surface portion, and is conductively connected to the conductive layer 33. The external electrode 345 is conductively connected to the internal electrode 343 at the side surface portion and is exposed on the outer surface of the piezoelectric element 34.

  The vibration generating source 3 configured as described above is connected to the excitation drive circuit 100 by drawing one wiring from the conductive layer 32 and drawing the other wiring from the external electrode 345. In this vibration source 3, since the elastic metal plate 31 and the piezoelectric element 34 are insulated by the insulating layer 32, no driving potential is supplied to the elastic metal plate 31, so that a large insulation is provided on the excitation drive circuit 100 side. Since there is no need to provide a transformer, the drive device can be reduced in size and price. Further, when the elastic metal plate 31 is not insulated, the external electrode 344 needs to be set at the ground potential for the safety of the vibration type conveying apparatus 10, so that a strict insulating cover or the like needs to be provided for the external electrode 345. However, in this embodiment, the insulating material can be simplified.

  Furthermore, in the vibration generating source 3 of the present embodiment, the piezoelectric element 34 has a laminated element structure (a structure in which each piezoelectric layer is driven in parallel in a laminated structure), so that the drive voltage can be lowered. For example, a piezoelectric element having a conventional structure requires a high drive voltage of about 200 to 400 V, but in this embodiment, a drive voltage of about 30 to 80 V is obtained by driving 3 to 5 piezoelectric layers in parallel. It is possible to drive. Therefore, the excitation drive circuit 100 does not require a booster circuit, and the absence of the booster circuit allows the drive device to be reduced in size and price.

  In the present embodiment, sets of the transport body 3, the connecting member 4, the first elastic support body 5, and the second elastic support body 7 are respectively provided at two positions before and after being separated in the transport direction F. . That is, the transport body 2 is elastically supported by the first elastic support body 5 and the second elastic support body 7 at two locations in the front and rear. Further, the vibration source 3 arranged in the front is arranged behind the first elastic support body 5 in the front, connected to the inertia body 6 arranged in the rear, and the vibration source 3 arranged in the rear is It arrange | positions ahead of the back 1st elastic support body 5, and is further connected to the inertia body 6 arrange | positioned ahead. That is, the inertial body 6 is arranged in the middle of the two sets of vibration generating sources 3 in the front-rear direction, and the two sets of vibration generating sources 3 are connected together to the common inertial body 6.

  The inertial body 6 has an inertial plate 6A connected to the vibration source 3 and an inertial block 6B fixed to the inertial plate 6A, and the inertial block 6B is suspended below the inertial plate 6A arranged at the upper part. It has a fixed structure. The inertia plate 6A is disposed immediately adjacent to the conveyance body 2, and the inertia block 6B is provided so as to protrude downward from the inertia plate 6A so as to overlap the same height range as the vibration generating source 3.

  Both the first elastic support 5 and the second elastic support 7 are plate-like elastic bodies, for example, leaf springs. The first elastic support 5 and the second elastic support 7 are arranged along a common straight line when viewed from the side. As a result, both elastic supports have support characteristics that are similar to those of a single plate-like elastic body between the base 1 and the carrier 2. That is, if the first elastic support 5 and the second elastic support 7 are provided at positions shifted in the front-rear direction, the direction is different from the original vibration direction S1 orthogonal to the posture of the vibration source 3. , Unnecessary vibration modes (for example, vibration modes swinging in the vertical direction) are generated, which may adversely affect the transport characteristics of the transport body 2, as described above. Is arranged along a common straight line, generation of unnecessary vibration modes can be suppressed.

  The common straight line is configured to be parallel to the extending direction of the vibration source 3. As a result, it is possible to efficiently transmit the bending vibration in the direction orthogonal to the extending direction of the vibration generating source 3 (the direction along the plate surface) to the first elastic support body 5 and efficiently vibrate the transport body 2. Can be made. In the present embodiment, by giving vibration S3 in a direction slightly inclined in the vertical direction with respect to the horizontal direction as indicated by the illustrated arrow to the transport body 2, parts not shown on the transport body 2 are moved in the transport direction F. It is comprised so that it can convey along. Therefore, in order to efficiently transmit such vibration, the vibration generating source 3 is set to a posture extending slightly in the front-rear direction with respect to the vertical direction, and the first elastic support 5 and the first The second elastic support 7 is in a posture extending in a direction parallel to the elastic support 7.

  Furthermore, since the lower end of the vibration generating source 3 is connected to the connecting member 4 and the upper end of the vibration generating source 3 is connected to the inertial body 6, the inertial body 6 can be easily brought close to the transport body 2, Moments generated by the carrier 2 and the inertial body 6 that vibrate in opposite phases can be reduced, and unnecessary vibration modes can be suppressed. Further, since the inertial body 6 (particularly the inertial block 6B) is arranged so as to overlap the height range of the vibration generating source 3, even if the mass and volume of the inertial body 6 are increased, the device 10 is moved in the height direction. It can be configured compactly.

  In the apparatus 10 configured as described above, when AC vibration is applied to the vibration generation source 3 and bending vibration is generated, the connecting member 4 and the inertial body 6 are bent on the vibration generation source 3 on both sides of the vibration generation source 3. Vibrate in the direction. The vibration S1 of the connecting member 4 is amplified by the first elastic support body 5 and the second elastic support body 7 with the base 1 as a fulcrum, and causes the transport body 2 to generate vibration S3. In addition, a vibration S2 having a vibration phase opposite to that of the connecting member 4 is generated in the inertial body 6 that is a free end.

  In the present embodiment, unlike the conventional vibration transfer device, one end of the vibration generating source 3 is connected to both the first elastic support 5 and the second elastic support 7, and the vibration generating source 3 Since the other end is connected to the inertia body 6, one end of the vibration source 3 is not configured to vibrate the transport body 2 directly and without limitation, so that the vibration S <b> 3 of the transport body 2 is in the transport direction F. It has been confirmed that the occurrence of noise along the top and bottom is reduced. That is, when shooting with high-speed video or the like, in the conventional transport device, the transport posture of the component is disturbed to the left and right, up and down, or the component occasionally moves in the reverse direction. However, in this embodiment, the parts are regularly sent in the transport direction accurately. And it was recognized that the vibration energy is efficiently transmitted to the parts by this, the conveyance direction F of the parts is easily aligned, and the conveyance speed is improved.

  Further, the base 2 is connected to the connecting member 4 via the second elastic support 7, and the carrier 2 is connected to the connecting member 4 via the first elastic support 5, and the vibration Since the inertial body 6 is connected via the generation source 3, vibration elements that vibrate in opposite phases are connected together. As a result, vibration energy transmitted to the base 2 is reduced. Therefore, it is possible to reduce adverse effects due to vibrations on adjacent devices and to suppress noise.

  Further, in the present embodiment, it is not necessary to use a vibration source 3, the first elastic support 5 and the second elastic support 7 having special and complicated shapes and structures, thereby reducing the manufacturing cost. be able to. In the case of the illustrated example, the vibration generating source 3, the first elastic support body 5 and the second elastic support body 7 are all formed of plate-like bodies. In addition, you may comprise the said 1st elastic support body 5 and the 2nd elastic support body 7 by an integral elastic member.

  With respect to the vibratory transfer device 10 equipped with the excitation drive circuit 100 described above and the vibration source 3 driven thereby, the supply voltage Vo of the DC power supply, the voltage detection value Vd, and the acceleration sensor are actually used. The results of examining the frequency dependence of the detected acceleration A of the piezoelectric element are shown in FIGS. FIG. 4 shows data when feedback control based on the voltage detection value Vd is not performed (that is, when the output voltage Vp from the inverter 130 is constant). The supply voltage Vo is 68 V DC, and the inverter 130 has a pulse width modulation of about 35%. And the output voltage Vp was measured at a constant value of 20V. FIG. 5 shows data when feedback control is performed so as to keep the voltage detection value Vd constant under the same supply voltage Vo.

  As shown in FIG. 4, when the drive frequency is changed without feedback control, the voltage detection value Vd exhibits a minimum value and the acceleration A exhibits a maximum value at the resonance frequency f1. This is because the impedance of the piezoelectric element 34 decreases at the resonance frequency f1, so that even if the supply voltage Vo (and the output voltage Vp) is constant, the drive voltage that is actually applied to the vibration source 3 decreases. Means that It can be seen from the data in FIG. 4 that the resonance frequency f1 can be detected by looking at the minimum point of the voltage detection value Vs without using an acceleration sensor.

  On the other hand, when feedback control is performed as shown in FIG. 5, since the voltage detection value Vd is held constant, there is no minimum point in the voltage detection value Vd even at the resonance frequency f1, but the voltage detection value Vd is held constant. Therefore, since the voltage command value (Vr−Vd or a value proportional to this) of the control signal S shows a maximum value, the voltage command value can be monitored without using an acceleration sensor as described above. Thus, the resonance frequency f1 can be known. In this case, since the voltage detection value Vd does not decrease and is constant even in the vicinity of the resonance frequency f1, the acceleration A of the element is significantly increased as compared with the case shown in FIG. This means that the piezoelectric element 34 can be driven more efficiently than before or as expected with a set voltage to be applied to the element.

  That is, in the conventional configuration, even if the output voltage Vp of the inverter is set appropriately, a voltage drop occurs due to the internal resistance of the switching element of the inverter and the resistance component of the inductance. Therefore, the actual both-end voltage Vs is lower than the output voltage Vp. In addition, since the voltage drop is determined by the resistance value and the drive current of the vibration source, the voltage Vs between both ends cannot be intentionally controlled unless the resistance value and the current value are grasped. Further, in the vicinity of the resonance frequency f1, the impedance characteristic of the piezoelectric element 34 is also likely to change, and the relationship between the output voltage Vp and the both-end voltage Vs is difficult to be constant, so it is extremely difficult to optimize the both-end voltage Vs. On the other hand, in the present embodiment, the voltage Vs between both ends is directly detected, and the output voltage Vp is controlled according to this, so that the voltage can be easily optimized. In addition, even when the same drive circuit for excitation is used for the conveying devices having different specifications as described above, the voltage Vs at both ends can be grasped, so that it can be easily handled.

  Further, when the vibration load connected to the vibration generating source 3 changes and the resonance frequency changes, the impedance of the piezoelectric element 34 changes. Therefore, in the conventional method, the voltage Vs at both ends changes even if the voltage command value is constant. However, this is not the case in the present embodiment in which the voltage Vs at both ends is detected and feedback control is performed. Furthermore, in the conventional method, it is difficult to obtain reproducibility of the conveyance characteristics due to element variations (impedance variations and resonance characteristics variations), but in this embodiment, the voltage actually applied to the piezoelectric element 34 is reliably controlled. In addition, since the element characteristics are not affected, a desired element acceleration can be obtained in a relatively stable state according to the both-end voltage Vs, and the reproducibility of the conveyance characteristics can also be obtained.

FIG. 6 shows an equivalent circuit of a circuit portion composed of the inverter 130, the inductors 140 and 150, and the piezoelectric element 34 of the present embodiment. Then, with this equivalent circuit, the drive current I, the voltage Vs across the element, and the phase difference ΔP were calculated. The result is shown in FIG. Here, the output voltage Vp of the inverter 130 is constant at 20 V AC. The inductor 140 is represented by an equivalent inductance L1 and an equivalent DC resistance R1, the inductor 150 is represented by an equivalent inductance L2 and an equivalent DC resistance R2, and the piezoelectric element 34 is connected in series with an equivalent inductance Lx, an equivalent capacitance Cx, and an equivalent resistance Rx. This is shown by a parallel circuit of a part (resonator component) and an equivalent capacitance Cy (braking capacity component). Then, the electrical characteristics in the vicinity of the resonance point were examined by the equivalent circuit. Here, the circuit constant of the piezoelectric element 34 was calculated based on a value measured by an impedance analyzer for a piezoelectric element actually incorporated as a vibration generation source. At this time, the resonance frequency of the vibration generating source 3 was fr = π / 2 · (Lx × Cy) ^1/2 = 342.3 Hz.

  In the above conventional resonance frequency measuring method, the phase difference ΔP is obtained from the output voltage Vp and the current I, and the applied power W = Vp × I × cosΔP is obtained thereby to detect the maximum point of the applied power as the resonance frequency. However, in this embodiment, the voltage Vs across the element is directly detected. As shown in FIG. 7, the minimum point of the element voltage Vs matches the resonance frequency f1.

  In the conventional method, it is necessary to detect the driving current I and calculate the applied power by obtaining the phase difference ΔP from the output voltage Vp. However, since noise is superimposed when the driving current I is detected, the accurate current I and It is actually difficult to obtain the phase difference ΔP. In particular, in the vibration source 3 using a piezoelectric element, the current I is usually as small as about several mA, so that it is not possible to obtain a more accurate applied power. On the other hand, in the present embodiment, since the voltage across the piezoelectric element 34 is directly detected, it is not necessary to obtain the current I and the phase difference ΔP, and it is easy only with the voltage detection value Vd of the voltage detected directly. And the resonance frequency f1 can be calculated | required correctly.

  Furthermore, in the present embodiment, the voltage detection means using the detection transformer 170 is provided. However, since only a voltage needs to be detected, an ultra-small transformer is sufficient, so that the excitation drive circuit can be reduced in size and cost. Can be achieved. Even when a charge charge is generated in the piezoelectric element 34, this charge is discharged on the primary side 171 of the detection transformer 170, so that a resistance for discharging the charge charge (a high resistance connected to both ends of the piezoelectric element) is generated. It becomes unnecessary. Further, when the piezoelectric element 34 is short-circuited, the voltage on the secondary side 172 of the detection transformer 170 becomes zero, so that the electrical short-circuit can be reliably detected. Therefore, a resistor for detecting overcurrent is not necessary, and wasteful power consumption can be prevented.

  The drive frequency is basically set to drive the piezoelectric element 34 at a frequency that matches the resonance frequency determined by the structure of the vibratory conveyance device 10. Therefore, if the structure of the transport device changes, the resonance frequency also changes greatly. If the vibration load of the transport body (weight of the transported object) changes even if the transport device has the same structure, the resonance frequency changes although it is very small. . FIG. 10 shows the frequency of the voltage detection value Vd and acceleration A when the vibration load is changed to (1) 0 g, (2) 25 g, (3) 35 g, (4) 95 g, (5) 160 g, (6) 250 g. It is a graph which shows dependence. Here, since the vibration load is usually a transported object, it is not fixed to the transport body, but in this experiment, the weight having the above weight was fixed to the transport body. In this case, this is not an increase in the weight of the conveyed product but an increase in the vibration load corresponding to the increase in the weight of the conveyed object. However, even when the weight of the conveyed product is increased, the resonance frequency and the acceleration are less changed, but qualitatively, it seems to bring about the same effect.

  As shown in FIG. 10, the frequency of the maximum point of acceleration A indicated by the solid line and the minimum point of voltage detection value Vd indicated by the broken line, that is, the resonance frequency, decreases as the vibration load increases. This is because the weight of the vibrating transport body increases, but in the actual transport apparatus, the resonance frequency may increase. This is because an actual apparatus is influenced by the elastic constant of the spring member connected to the piezoelectric element, the counterweight, the overall mechanical structure, and the like, so that a complicated vibration system is configured. Further, in the actual vibratory transfer device, a part of the vibration energy is used as the transfer energy of the transfer object, so that the acceleration is lower than in the illustrated example, and the Q value is consequently reduced. This corresponds to an increase in the resistance Rx in the equivalent circuit shown in FIG.

  Further, FIG. 10 shows that the peak height of the acceleration A and the voltage drop amount at the minimum point of the voltage detection value Vd are substantially proportional. This is because the characteristics in the vicinity of the resonance point of the piezoelectric element are equivalent to the electrical LCR resonance circuit, and the frequency characteristics of the mechanical amplitude and the electrical impedance are similar. Therefore, it is possible to obtain acceleration based on the electrical impedance characteristic obtained as the frequency characteristic of the electrical detection value Vd, and therefore it is possible to control the acceleration without using an acceleration sensor as in the prior art. Recognize.

  Next, FIG. 11 shows a voltage detection value Vd (shown by a solid line) and an acceleration A (shown by a broken line) when the drive frequency is swept from 60 Hz to 400 Hz under the same conditions as those when the vibration load is set to zero. ) Is measured. The voltage detection value Vd indicated by the solid line in the figure gradually decreases as the drive frequency is increased, and eventually increases after greatly decreasing in the resonance point vicinity region K, but after passing through the resonance point vicinity region K, It will gradually fall again. The reason why the voltage detection value Vd gradually decreases as the drive frequency increases in the region excluding the resonance point vicinity region K is that the braking capacity Cy exists in the equivalent circuit shown in FIG. . That is, the piezoelectric element can be basically represented by an LCR resonance circuit represented by Lx, Cx, and Rx shown in FIG. 6, but is a braking component that is a capacitive component that does not contribute to vibration connected in parallel with the LCR resonance circuit. Since the capacitance Cy exists, the impedance characteristic of the region other than the resonance point vicinity region K is determined.

  On the other hand, the voltage detection value Vd when the braking capacity Cy is increased in a pseudo three-fold manner is indicated by a one-dot chain line in the figure, and the acceleration A at the same time is indicated by a two-dot chain line in the figure. At this time, the voltage detection value Vd outside the resonance point vicinity region K gradually increases as the drive frequency increases. This is because the inductors 140 and 150 and the braking capacity Cy constitute a resonance circuit. In this case, the resonance detection point of the resonance circuit exists in the vicinity of 1.3 kHz. Vd gradually increases.

  In the case of the present embodiment, since the piezoelectric element 34 has a laminated structure in which a plurality of element parts connected in parallel is laminated, the braking capacity Cy of each layer is added to add the entire structure. Increases braking capacity. Therefore, it is considered that the braking capacity is greatly affected as compared with the case of using a single-layer piezoelectric element.

  Taking the above points into consideration, the following procedure is performed, so that the acceleration A of the piezoelectric element can be maintained substantially constant even when the vibration load changes somewhat. First, the drive frequency is swept to measure the both-ends voltage Vs in a region excluding the region K near the resonance point shown in FIG. 11 (region where the effect corresponding to the LCR resonance circuit composed of Lx, Cx, and Rx is dominant). Then, the base curve B (shown dotted line) of the voltage detection value with respect to the drive frequency is acquired from the profile of the voltage detection value Vd. This base curve B is also indicated by a dotted line in FIG. 12 showing an example of the profile near the resonance point. As shown in FIG. 11, the base curve B changes to the right or the right as a whole, and changes depending on the braking capacity Cy and the values of L1, L2, R1, and R2 of the inductors 140 and 150. This is for accurately obtaining the drop characteristic of the voltage detection value Vd in the vicinity of the resonance point (due to the impedance change by the LCR resonance circuit composed of Lx, Cx, and Rx). Therefore, the same base curve B can be used as long as it is a vibration type conveying apparatus having the same configuration, and it can also be obtained from the parameters such as Cy, L1, L2, R1, and R2. Further, when it is less necessary to consider the base curve B in terms of required accuracy in terms of parameters (such as when the base curve is close to a horizontal line), the calculation and use of the base curve B may be omitted.

  Next, a profile in the vicinity of the resonance point of the voltage detection value Vd1 indicated by a solid line in FIG. 12 is obtained by a sweep operation in a drive frequency region within a predetermined range, and the voltage detection value Vd1 at the resonance point (that is, an illustration showing the resonance frequency f1). The difference between the voltage value on the base curve B and the voltage value at the intersection of the perpendicular line indicated by the alternate long and short dash line and the characteristic curve (Vd1) indicating the frequency characteristic of the voltage detection value is calculated as the voltage drop amount ΔVd1. And it drive | operates with the drive frequency which corresponds to this resonance frequency f1.

  At this time, the driving may be continued as it is at the resonance frequency f1 detected first, but it is also possible to make a fine correction of the driving frequency as follows, assuming a change in the resonance frequency. . In other words, the drive frequency may be swept back and forth slightly to detect the minimum point of the voltage detection value Vd1, and control may be performed so that the drive frequency always matches the resonance frequency obtained at the minimum point. At this time, the drive frequency sweep operation is always performed, and the drive frequency may always change back and forth around the actual resonance frequency (minimum point of the voltage detection value Vd), or the drive frequency sweep operation. May be performed intermittently (regularly or irregularly), and may be controlled each time so that the drive frequency matches the resonance frequency obtained as a result of the sweep operation. In this way, even if the actual resonance frequency fluctuates somewhat, it is possible to efficiently operate at a drive frequency that almost always matches the resonance frequency.

  Next, in the state where the drive frequency is set to the reference frequency f1, while monitoring the voltage detection value Vd, when the fluctuation amount of the voltage detection value Vd exceeds a certain threshold value, the vibration load It is determined that has changed, and the following correction operation is executed. Here, in FIG. 12, the voltage detection value (characteristic curve) Vd2 after changing the vibration load is indicated by a broken line, and the corrected voltage detection value (characteristic curve) Vd3 is indicated by a two-dot chain line. However, in the case of the example shown in FIG. 12, unlike the case shown in FIG. 10, the vibration load is not fixed to the carrier, and the particulate weight is not fixed on the carrier. The change in is very small. When the drive frequency is finely corrected by searching for the resonance frequency as described above, the fluctuation amount of the resonance frequency f1 detected in the sweep operation for performing the fine correction exceeds a certain threshold value. The following correction operation may be executed at the same time, or the following correction operation may be executed when the fluctuation amount of the voltage drop amount ΔVd1 calculated in the same manner exceeds a certain threshold value. May be.

  In the correction operation of the present embodiment, first, the drive frequency is swept within a predetermined range (in the case where the drive frequency is finely corrected as described above, the sweep range is further expanded as necessary. And the detected resonance frequency f2 is detected, and the drive frequency is corrected so as to match the resonance frequency f2. In this case, the above threshold value, which is a comparison target of the fluctuation amount of the voltage detection value Vd1, the resonance frequency f1, or the voltage drop amount ΔVd1, is set according to the degree to which the fluctuation of the acceleration A is desired to be suppressed. Therefore, by simply correcting the drive frequency to the newly found resonance frequency f2, as shown in FIG. 13, the post-change acceleration A2 (shown broken line) is unacceptable compared to the pre-change acceleration A1 (shown solid line). The acceleration cannot be maintained as before the change. However, as described above, it is known that the voltage drop amount has a correlation with the impedance change of the piezoelectric element and is proportional to the acceleration A as shown in FIG. Therefore, the voltage drop amount ΔVd2 is calculated after the correction of the driving frequency, and the fluctuation ratio R = ΔVd2 / ΔVd1 between the voltage drop amount ΔVd1 before the change and the voltage drop amount ΔVd2 after the change is used as the correction parameter. Then, even after the vibration load is changed, the acceleration is changed before and after the fluctuation of the vibration load by correcting the acceleration so that the acceleration is R times the fluctuation ratio that is the correction parameter.

  In practice, since it is only necessary to suppress fluctuations in acceleration, as an example of a method for correcting the acceleration after the change of the vibration load, a method in which a value obtained by multiplying the voltage command value by the ratio R is set as a new voltage command value. Can be considered. The corrected voltage detection value Vd3 shown in FIG. 12 is corrected by multiplying the voltage command value included in the control signal S output from the control unit 180, which is the inverter control means, by the ratio R, and a new voltage command value. It is an experimental value detected in the case of. In this case, as shown in FIG. 13, the acceleration indicated by the two-dot chain line after the correction is compared with the acceleration A2 after the vibration load is greatly reduced with respect to the acceleration A1 before the change. A3 is a value almost approximate to the acceleration before the change.

  The corrected data shown in FIGS. 12 and 13 are experimental results when the voltage command value output from the control unit 180 is corrected by the ratio R, and the accelerations A1 and A3 do not exactly match. , Acceleration fluctuations can be sufficiently suppressed. Here, the details of each data shown in FIGS. 12 and 13 are as follows. Before the change, a voltage command value of 3V (5V is 100%) is given from the control unit 180 to the PWM circuit 190, the resonance frequency and the drive frequency f1 at this time are 268.5 Hz, and the base of the voltage detection value Vd1 at this frequency The value at the resonance point of the curve was 23.6 V, and the acceleration A was 22.4 G. Further, the voltage drop ΔVs1 at this time was 2.3V. Thereafter, when the 500 g of the particulate weight is placed on the carrier without being fixed, the resonance frequency becomes 268.8 Hz, and the value at the resonance point of the base curve of the voltage detection value Vd2 at this frequency is 23.5 V, The acceleration was 16.3G. The voltage drop amount ΔVd2 at this time was 1.7V. Therefore, the voltage command value is changed to a value of 4.2 V obtained by multiplying the original voltage command value 3 V by the voltage drop variation ratio R = ΔVd1 / ΔVd2 = 1.4. As a result, the resonance frequency was 268.5 Hz, the value of the base curve of the voltage detection value Vd3 at this frequency was 33.8 V, the voltage drop amount was 1.8 V, and the acceleration was 23.2 G. Each of the above values is rounded off to the first decimal place.

  The correction method using the variation ratio R as a correction parameter is not limited to the above method, and any method may be used as long as it can suppress the change in acceleration before and after the change of the vibration load. Here, the target to which the correction parameter is applied is the voltage control parameter. The voltage control parameter is not limited to the voltage command value shown in the above example. For example, a value obtained by multiplying the voltage detection value Vd2 detected at the resonance point after the change of the vibration load by the ratio R becomes a corrected voltage detection value Vd3, that is, Vd3 = R · Vd2 = Vd2 · ΔVd2 / A method of setting a new voltage command value such that the minimum value of the voltage detection value at the resonance point is set as the voltage control parameter and becomes a correction value so as to be ΔVd1 can be considered. Further, a voltage value near the resonance point in the base curve may be used as the voltage control parameter. In this case, the voltage command value is set so that the value of the base curve becomes a value corrected by the ratio R. For example, in the above example, since the value at the resonance point of the base curve B after the vibration load is changed is 23.5 V, when this is multiplied by the ratio R = 1.4, it becomes 32.9 V. Therefore, a new voltage command value is set so that the value at the resonance point of the corrected base curve B approaches 32.9V.

  In the above example, the method of setting the correction parameter as the voltage drop amount is described on the assumption that the feedback control of the voltage detection value Vd is not performed. However, when the feedback control of the voltage detection value Vd is performed, the feedback control is temporarily performed. Either stop and detect the same correction parameter as above, or use the fluctuation ratio of the voltage increase of the voltage command value instead of the fluctuation ratio of the voltage drop as the correction parameter. In this case, a voltage reference value Vr that is a control target value can be used as the voltage control parameter. That is, a new voltage reference value Vr corrected by multiplying the voltage reference value Vr before correction by the correction parameter (the fluctuation ratio of the voltage increase amount) is calculated, and thereafter, the new voltage reference value is set as the control target. As a value, feedback control of the voltage detection value Vd is performed.

  The vibration transfer device and the drive circuit for excitation according to the present invention are not limited to the above-described illustrated examples, and various changes can be made without departing from the scope of the present invention. For example, as the above-described vibration type conveying apparatus 10, an apparatus having a linear conveying path is illustrated, but an apparatus having a helical conveying path such as a bowl-type parts feeder may be used. Further, the present invention is not limited to the vibration-proof type vibration transfer device having the inertial body 6 described above, and may be applied to various devices having a transfer body connected to the piezoelectric driving body directly or via a spring material. it can.

The schematic block diagram of the drive circuit for excitation of embodiment. The schematic side view of the vibration type conveying apparatus of the embodiment. The schematic front view (A) of the vibration type conveying apparatus of embodiment and the schematic plan view (B) of the part except a conveyance body. The graph which shows the frequency dependence of the supply voltage in the state which does not perform feedback control, both-ends voltage, and acceleration. The graph which shows the frequency dependence of the supply voltage in the state which implemented feedback control, both-ends voltage, and acceleration. The equivalent circuit diagram of the circuit part from an inverter to a vibration generation source. The graph which shows the frequency dependence of the electric current I computed with the equivalent circuit of FIG. 6, phase difference (DELTA) P, and both-ends voltage Vs. Sectional drawing which shows the specific structural example of a vibration generation source. The expanded sectional view which shows the structure of a piezoelectric element typically. The graph which shows the change of the frequency characteristic of the acceleration and voltage detection value by the change of a vibration load. The graph which shows the change of the frequency characteristic of the acceleration and voltage detection value by the difference in braking capacity. The graph which shows the frequency characteristic of the voltage detection value before a change when a vibration load changes, after a change, and after a correction | amendment. The graph which shows the frequency characteristic of the acceleration before a change when a vibration load changes, after a change, and after correction | amendment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Vibration generating source, 10 ... Vibration type conveying apparatus, 100 ... Excitation drive circuit, 110 ... Commercial power supply, 120 ... DC power supply, 130 ... Inverter, 140, 150 ... Inductor, 160 ... Vibration generating source, 170 ... Detection transformer , 180 ... control unit, 190 ... PWM circuit, A ... acceleration, Vo ... supply voltage, Vp ... output voltage, Vs ... both-ends voltage, Vd, Vd1, Vd2, Vd3 ... voltage detection value (characteristic curve), ΔVd1, ΔVd2, ΔVd3: Voltage drop amount, I: Current, ΔP: Phase difference, B: Base curve

Claims (7)

In the vibration type conveying apparatus that conveys the conveyed object by vibrating the conveying body by applying an AC voltage to the vibration generating source,
As the vibration generation source, an elastic metal plate directly or indirectly connected to the carrier, and an adhesive layer bonded to the elastic metal plate via an insulating layer, a plurality of piezoelectric layers and a plurality of electrode layers Using a piezoelectric driving body having a laminated piezoelectric element in which are alternately laminated,
A DC power supply that outputs the required DC voltage;
An inverter that converts the AC voltage into an AC output voltage by PWM driving and applies the AC voltage to the piezoelectric element;
An inductor connected between the inverter and the piezoelectric element;
Voltage detecting means for directly detecting the voltage across the piezoelectric element;
Inverter control means configured to be able to set the frequency and voltage value of the inverter and to control the inverter according to the voltage detection value of the voltage detection means;
A vibratory conveying device comprising:   2. The vibratory transfer apparatus according to claim 1, wherein the inverter control means controls the inverter so as to keep the voltage detection value constant.   3. The vibration type according to claim 1, wherein the voltage detection unit includes a detection transformer in which a voltage at both ends of the vibration generation source is applied to a primary side and a secondary side is connected to the inverter control unit. Conveying device.   The inverter control means includes resonance point detection means for obtaining a resonance frequency by changing a frequency of the output voltage while detecting a minimum point of the voltage detection value while maintaining a voltage command value constant. The vibratory transfer device according to any one of claims 1 to 3.   The inverter control means includes a resonance point detection means for obtaining a resonance frequency by changing the frequency of the output voltage while detecting the maximum value of the voltage command value while controlling the voltage detection value to be constant. The vibratory transfer device according to any one of claims 1 to 3.   The inverter control means corrects a voltage control parameter according to a fluctuation ratio of a voltage drop amount of the voltage detection value or a voltage increase amount of a voltage command value at a resonance point, thereby suppressing an acceleration fluctuation of the piezoelectric element. 6. The vibratory transfer apparatus according to claim 1, further comprising a control unit. In a vibration-type transfer device that transfers an object by vibrating an object by applying an AC voltage to a vibration source, the vibration source includes a piezoelectric element for excitation, and a DC power source that outputs a required DC voltage And an inverter that converts the DC voltage into an AC output voltage by PWM drive and applies it to the vibration generating source, an inductor connected between the inverter and the piezoelectric element, and a voltage across the piezoelectric element. Voltage detection means including a detection transformer for direct detection, and the frequency and voltage value of the output voltage of the inverter can be set, and the inverter can be controlled according to the voltage detection value of the voltage detection means And an inverter control means.

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